The present invention relates generally to door security devices, and particularly to door security devices allowing partial opening of a door while maintaining protection against forced entry.
Residential door security is essential. Every residence has locking doors barring unauthorized entry, especially forced entry. The greater protection against forced entry, the greater the security enjoyed by the inhabitants. Extra security devices, beyond a latch set and dead bolt, are often used once the occupants are inside the building. Such devices are not accessible from the outside and, therefore, are less vulnerable to compromise from the outside. In many situations it is desirable to allow partial opening of the door, but retain protection against forced entry. Door chains selectively couple the door to the surrounding frame to allow partial opening of the door while maintaining some degree of security. Door chains, however, lack good security because of the typically weak attachment of the chain components to the door and surrounding door frame. Once the door is open, the chain itself can be easily broken, or can be broken away from the door or from the door frame.